Refrigeration



REFRIGERAT ION Filed May 28, 1937 I W WM MA I'T ORNEY Patented Feb. 7,1939 PATENT OFFICE REFRIGERATION Hugo M. Ullstrand, Evansville, Ind.,assignor to Servel, Inc., New York, N. Y., a corporation of DelawareApplication May 28, 1937, Serial No. 145,178

6 Claims.

My invention relates to a transfer vessel type of absorptionrefrigeration system and it is an object of the invention to provide animproved liquid level control system in which rate of liquid 5 transfervaries automatically with refrigeration requirements as set forth withparticularity in the following description and the accompanying drawingforming part of this specification and in which the single figure showsmore or less diagrammatically a refrigeration system embodying theinvention.

A generator I is heated by suitable means, such as a gas burner Thegenerator is divided by a partition l2 into an upper chamber I3 and alower chamber M. An opening I 5 provides for flow of liquid from chamber|3 downward into chamber M. A vent conduit 6 connects the upper parts ofchambers l3 and 14. The upper part of chamber I3 is connected by aconduit ii to a condenser I8. The condenser is connected by a conduit Hito an evaporator 2|! located in v a thermally insulated refrigeratorstorage compartment 2|. Flow of liquid through conduit |9 to theevaporator 20 is controlled by an expansion valve 22 or other suitablepressure reducing control device.

An absorber 23 comprises a header 24 and a downward looped conduit 25.The header 24 is divided by a partition 26 into a float chamber 21 30and an overflow chamber 28. Chambers 21 and 28 communicate over the topof partition 26. One end of the looped conduit .25 is connected to thebottom of chamber 21 and the other end of conduit 25 is connected to thebottom of chamber 28. In the upper part of chamber 21 is an overflow pan29. Chambers 21 and 28 are also interconnected by a downward loopedconduit 58, One end of conduit 58 is connected to the bottom of chamber21 and the other end is open within the lower part of chamber 28 andformed with a goose neck .59.

The lower part of the generator I 0 is connected by a conduit38,passages 3| and 32 in the absorber casing, and conduit 33 to theinterior of the amorber. Conduit 33 discharges into the overflow pan 29.Flowof liquid through conduits 3| and 32 is 'controlled'by valve 34operated by a float 35 in the absorber float chamber 21. A con-' duit 31is connected fromthe evaporator 20 to the absorber coil 25. One end of aconduit 38 is connected to a transfer vessel 40 and the other end isconnected to the absorber chamber 28. A small opening 68 affordscommunication from the lower part of the absorber chamber 28 intoconduit 38. The transfer vessel 40 is also connected to the absorber bya conduit 4| of which one end i" connected to the transfer vessel andthe other end extends into the overflow pan 29.

The lower part of the transfer vessel 40 is connected by a. conduit 42to the upper chamber i3 5 of the generator Ill. The upper part oftransfer vessel 4|] is connected by a conduit 43 to conduit H. In thetransfer vessel 40 are valves 44, 45,

46 and 41, all of these valves being connected to a valve operating rod48 so as to be operated to- 10 gether. On valve rod 48 is slidablymounted a float 49 which imparts movement to the valve rod 48 throughpins 58 and 5|. A cam 52 on rod 48 and spring pressed dogs 53 cause snapaction of the valve rod 48 up and down as force is correl5 spondinglyapplied thereto by the float 49. The transfer vessel valves are arrangedas shown so that valves 44 and 45 are closed when valves 45 and 41 areopen, and vice versa. Valve 44 controls a passage 54 with whichcommunicates con- 20 duit 38. Valve 45 controls a passage 55 with whichcommunicates conduit 4|. Valve 46 controls a passage 56 with whichcommunicates conduit 43. Valve 41 controls a passage 51 with whichcozmnunicates conduit 42,

In operation, a vaporous refrigerant fluid, such as ammonia, is expelledfrom solution in an absorbent, such as water, by heating in thegenerator Hi. The refrigerant vapor flows from the generator chamber l4through conduit l6, upper chamber i3, and conduit l1, to the condenserIS. The ammonia vapor is condensed to liquid in the condenser 8 and theliquid flows through the expansion valve 22, or other suitable pressurereducing device, into the evaporator 20. The liquid ammonia vaporizes inthe evaporator, producing a refrigerating effect in the refrigeratorcompartment 2|.

Ammonia vapor flows from the evaporator 28 through conduit 31 into thelower part of the absorber coil .25. The ammonia vapor flows upward incoil 25 and is absorbed into solution with absorption liquid whichfloods the coil 25. Upward flow of vapor through coil 25 causes flow ofabsorption liquid from the absorber chamber 21 through absorber coil 25into the absorber chamber 28. Liquid flows from chamber 28 throughconduit 58 into chamber 21. Y

weakened absorption liquid flows from the lower part of the generatorill through conduit 30, passages 3| and 32, and conduit 33 into theoverflow pan 29 and thence into the absorber chamber 21. Flow ofabsorption liquid from passage 3| to passage 32 is controlled by thefloat valve 34 responsive to level of liquid in chamber uid flows fromthe absorber chamber .28 through.

orifice .68 into conduit 38. The rate of flow of liquid from chamber 28into conduit 38 is steady and constant so long as the surface level ofliquid in chamber 28 remains constant, so that rate of flow of liquidfrom the absorber through conduit 38 to the transfer vessel 40 is steadyand constant when this condition exists. However, the weak solutionconduit 30 is in thermal exchange relation with the right hand leg ofthe U-shaped conduit 58 so that,upon increase in demand forrefrigeration, when the heat input to the generator I is increased andthe temperature in the generator rises, the resulting higher temperatureof the weak liquid flowing through conduit 30 causes the richer solutionin conduit 58 to boil, the resulting vapor rising in the right hand legof the U-shaped conduit 58 preventing flow of liquid through thisconduit. Under this condition, liquid cannot flow from chamber 28 tochamber 21 in the absorber. Also, the rate of flow of liquid through theabsorber coil 25 from chamber 21 to chamber 28 increases because of thegreater amount of vapor flowing through conduit 31 upon increase indemand for refrigeration. This causes the surface level of liquid inchamber 28 to rise above that in chamber 21. The resulting increasedhead of liquid above orifice 60 causes a greater rate of flow ofenriched absorption liquid 85 from chamber 28 through conduit 38 to thetransfer vessel,

Assuming that the transfer vessel 48 is empty so that the float 49 is inits lower position, valves 41 and 46 are closed and valves 44 and 45 areopen.. The enriched absorption liquid flowing through conduit 38 fromthe'absorber enters passage 54 and passes theopen valve 44 into thetransfer vessel. As the transfer vessel fills with liquid, vapor escapespast the open valve 45 through passage 55 and conduit 4| into theabsorber where it bubbles into liquid in the overflow pan 28 and isabsorbed in the liquid. Liquid rises in the transfer vessel 40 until thefloat 49 overcomes the resistance of the toggle mechanism to snap valves44 and 45 closed and valves 46 and 4! open. This is the position of thevalves shown in the drawing. Liquid in the transfer vessel nowdischarges through passage 51 and conduit 42 into the chamber I3 of thegenerator Ill. The pressures in the generator and transfer vessel areequalized by flow of vapor from conduit I! through conduit 43 andpassage .58 into the transfer vessel. As liquid flows out of thetransfer vessel into the generator, the net weightof the float 48increases until it overcomes the resistance of the toggle mechanism tosnap valves 41- and 46 closed and valves 44 and 45 open. This cycle isrepeated at intervals dependent upon the rate of flow of liquid from theabsorber to the transfer vessel through conduit 38. Thus, as the flow ofliquid through conduit 38 increases responsive to increase in demand forrefrigeration, the operation of the transfer vessel becomes more rapid.'The rapidity of operation of the transfer vessel increases until themaximum rate of flow through conduit 38 is reached when liquid overflowsthe top of partition 26 into chamber 21.

The enriched absorption liquid transferred into chamber l3 of thegenerator Ill flows through the flow of liquid through the heatedchamber I4 is a steady flow. The rate of flow of liquid through theopening l5 from the chamber l3 into chamber l4 also increases as thelevel of liquid in chamber l3 increases so that liquid circulationthrough and between the generator and absorber takes place automaticallyat a rate responsive to refrigeration requirements.

Various changes may be made within the scope of the invention which isnot limited as shown in the drawing or set forth in the foregoing partof this specification but only as indicated in the following claims.

What is claimed is: r

1. An absorption refrigeration system including an absorber, agenerator, liquid level responsive means "for controlling flow of liquidfrom said generator to saidabsorber, a device for transferring liquidbetween said absorber and generator at a rate responsive to flow ofliquid to said device, and means for varying flow of liquid from saidabsorber to said device responsive to heat inputto said generator.

2. An absorption refrigeration system including an absorber, agenerator, a conduit for weakened absorption liquid from said generatorto said absorber, and means for circulating absorption liquid betweensaid absorber and generator at a rate responsive to temperature ofweakened absorption liquid in said conduit.

3. 'An absorption refrigeration system including an evaporator, anabsorber, a generator, a device for transferring liquid between saidabsorber and generator, aconduit for vapor from said evapolater to saidabsorber, said absorber being constructed and arranged so that flow ofvapor thereto from said evaporator causes local circulation of liquid inthe absorber, means for flowing liquid from said absorber to saidtransfer device, and means for interrupting said local circulation, saidfirst means causing greater flow of liquid from said absorber to saidtransfer device upon interruption of said local circulation.

4. A method of refrigeration which includes conducting absorption liquidfrom a place of vapor expulsion to a place of absorption. con ductingenriched absorption liquid from said place of absorption to a place oftransfer, conducting liquid from said place of transfer to said place ofexpulsion at intervals dependent upon rate of liquid conduction to saidplace of transfer, and conducting liquid to said place of transfer at arate responsive to temperature adjacent said place of expulsion.

5. A method of refrigeration which includes conducting absorption liquidfrom a place of vapor expulsion to a place of absorption, conductingenriched absorption liquid from said place of absorption to a place oftransfer, conducting liquid from said place of transfer to said place ofexpulsion at intervals dependent upon rate of liquid conduction to saidplace of transfer, and conducting liquid to said place of transfer at arate responsive to temperature of absorption liquid being conducted tosaid place of absorption. 6. A method of refrigeration which includestransferring absorption liquid between a place of absorption and 'aplace of expulsion through an intermediate place of transfer at' a ratedependent upon rate of arrival of liquid at said place of transfer, andcontrolling said rate of arrival responsive to temperature of absorptionliquid.

, HUGO M. ULLSTRAND.

